Conventionally, time division duplexing (TDD) and frequency division duplexing (FDD) have been known as duplex systems. Herein, TDD allows for transmission and reception using the same frequency band in divided time slots while FDD allows for transmission and reception using divided frequency bands.
The 3GPP (3rd Generation Partnership Project) has standardized a wireless communication system (an LTE system), called LTE (Long Term Evolution), using FDD and TDD. The LTE system using TDD is called a TD-LTE system to be discriminated from another LTE system using FDD.